Gripping apparatus



P 6, 1966 A. cs. GRIFFIN 3,247,565

GRIPPING APPARATUS Filed March 9, 1964 2 Sheets-Shea'l'. l

JA 22 9O as 22 INVENTOR.

VIN G. GRIFFIN BYm/ ATTORNEY April 26, 1966 Q A. G. GRIFFIN GRIPPING APPARATUS 2 Sheets-Sheet 2 Filed March 9, 1964 INVENTOR. 7 ALV G. GRIFFIN ATTORNEY United States Patent 3,247,565 GRIPPING APPARATUS Alvin G. Grifiin, 1006 Old Gate Road, Pittsburgh, Pa. Filed Mar. 9, i964, Ser. No. 350,391 7 Claims. (Q3. 24-263) This invention relates to gripping apparatus, and more particularly to gripping apparatus of the quick-release type wherein a pair of opposed gripping members are employed one of which has at least one roller member associated therewith.

As advances are made in the metallurgical field, new alloys become available which are harder than .any presently known alloys. As each new alloy is produced, its physical characteristics must be measured in order to ascertain in what areas it may be used. One group of these physical characteristics requires that the specimen be elongated by the application .of tensile forces to determine its tensile strength, yield point and the like.

Because of the extreme hardness of these alloys, conventional gripping apparatus most often fails to hold the specimen. That is to say, the specimen slips from between the jaw members of the, gripping apparatus. One alternative, then, is to employ jaw members made from the alloy being tested. This, of course, is impractical. Another alternative is to apply greater pressures on the jaw members in order-to hold the specimen. In this -instance, however, the knurl ridges, normally found in conventional jaw members, are crushed 'by the greater pressure resulting in slippage of the test specimen.

In the present invention, the gripping force of at least one of the jaw members is concentrated along one or more parallel lines which extend transverselyof the test specimen and the direction of pull. This construction is contrary to conventional jaw members whe-reinthe gripping force is spread over an area of the specimen gripped. Furthermore, through the useof the present gripping apparatus, thatrportion of the specimen which is gripped is not noticeably marred.

Although the above remarks havebeen directed to the use of the present gripping apparatus in conjunction with test specimens of unusual hardness, the present gripping apparatus may be adapted for other uses as will be readily apparent from-the detaileddescription which follows.

Accordingly, as an overall object, the present invention seeks to provide gripping apparatus of improved construction wherein a test specimen is firmly gripped regardless of its hardness.

Other important objects of the present invention include:

To provide gripping apparatus which adjusts automatically to the thickness of the specimen being gripped;

To provide gripping apparatus wherein one of the opposed jaw members is movably mounted thereby permitting major adjustments to be made manually in the spacing between the opposed gripping members to correspond with the thickness of the specimen being gripped;

To provide gripping apparatus which is adapted to'grip a plurality of elements for pulling the same;

To provide gripping apparatus, adapted to grip a plurality of elements for pulling'thesame, which apparatus automatically adjusts to minor variations in the thickness of the elements;

To provide gripping apparatus by which an elongated element or elements may be progressively moved along a path of travel by-sequentially gripping the element or elements at spaced points along its length; and

To provide gripping apparatus wherein the release of the elements being gripped is automatic.

In accordance with one embodiment of the present invention, gripping apparatus is provided through which an elongated element may extend. A pair of opposed gripping members serve to grip the element during movement of the gripping apparatus in one direction and which also release the element gripped during movement of the gripping apparatus in the reverse direction. Means is provided for moving one of the gripping members toward or away from the opposed gripping member thereby permitting adjustments of the spacing between the gripping members to correspond with the thickness of the element to be gripped. This embodiment may be mountedon a carrier member which is supported for reciprocal movement along a straight-line path of travel. Through the use .of this gripping apparatus, an elongated element may be progressively moved, in steps, along the aforementioned path of travel. To accomplish this, the gripping apparatus sequentially grips, moves and releases the element and thereafter returns to its starting point preparatory to repeating the sequence.

In accordance with an alternative embodiment of the invention, gripping apparatus .is provided through which a plurality of elongated elements may extend. A pair .of opposed gripping members serve to .grip the elements during movement of the gripping apparatus inone direction and which release the elements gripped during move- ;ment of the gripping apparatus in the reverse direction. Means is provided for moving one of the gripping members toward and away from the other gripping member thereby permitting adjustment of the spacing between the gripping members to correspond with the thickness of the, elements being gripped. Means also is provided for automatically adjusting for minor variations in the thickness of the elements being gripped. That is to say, each element may have a thickness which is slightly different from the thickness of the other elements.

According to a further alternative embodiment of the present invention, gripping apparatus is provided having a pair of opposed gripping members between which an end portion of the element to be gripped is inserted. One of the gripping members has a row of inclined surfaces upon each of which is disposed a -.roller member. Means is provided for biasing the other gripping member toward the element to be grippedthereby automatically providing an initial engagement therewith. This embodiment of thepresent gripping apparatus is particularly useful-in stretcher leveler apparatus, drawbenches and the like.

-In accordance with a :still further alternative embodiment of the present invention, gripping apparatus is provided having a pair of opposed gripping members each of which is slideably mounted on a suitable carrier housing.

The gripping members .aremounted so as to converge toward one another and therefore thisembodiment comprises seif-centering gripping apparatus. Both .of the gripping members arebiasedtoward the element tobe gripped thereby automatically adjusting the thickness of thespecimen being gripped and also automatically centering the specimen being gripped with respect to thegripping apparatus and other extrinsic measuring components.

The above and otherobjects and advantages of the present invention will become apparent fromthe following detailed description by reference to the accompanying drawings, in'which:

FIGURE 1 is a front view of one embodiment of the present gripping apparatus;

FIG. 2 is a cross-sectional view taken along the line IIII ofFIG. 1;

-FIG. 3 is a view schematically, illustrating the use of the gripping apparatus of -FIGS. 1 and 2 in conjunction with an extrusion apparatus;

FIG. 4 is a fragmentary cross-sectional view, taken along the line IVIV of FIG. 5, illustrating an alternative embodiment of the present gripping apparatus;

FIG. 5 is a cross-sectional view taken along the line V-V of FIG. 4;

FIG. 6 is a fragmentary isometric view illustrating certain features of the gripping apparatus of FIGS. 4 and 5;

FIG. 7 is a side view of a further alternative embodiment of the present gripping apparatus;

FIG. 8 is a cross-sectional view, taken along the line VIII-VIII of FIG. 7, further illustrating the gripping apparatus of FIG. 7;

FIG. 9 is a side view of a further alternative embodiment of the present gripping apparatus; and

FIG. 10 is a fragmentary cross-sectional view, on an enlarged scale, illustrating the arrangement of roller members employed in the gripping apparatus of FIG. 9.

Referring now to FIGS. 1 and 2, a gripping apparatus, generally indicated by the numeral 10, is shown comprising a pair of plate means 12, 14 having a crossplate 16 secured to the tops thereof by means of bolts 18 (only one shown). Associated with the plate means 12, 14 are opposed upper and lower gripping members 20, 22. The lower gripping member 22 is secured to the lower end of the plate means 12, 14 by means of horizontally extending bolts 24. The upper gripping member 20 is connected to the plate means 12, 14 by means of a pair of adjusting bolts 26 each having a knurled head 28 for turning the same. Each of the adjusting bolts 26 is threaded into the crossplate 16 and has a lower end 30 rotatably secured to the upper gripping member 20, for example, by means of pins 32 extending horizontally through the upper gripping member 20 and engaged in a groove 34 formed in the lower end 30. Thus, the upper gripping member 20 may be moved toward and away from the lower gripping member 22 by means of the adjusting bolts 26. If desired, locking nuts 36 may be provided for locking the upper gripping member in any desired position with respect to the lower gripping member 22.

In the present invention the upper gripping member has a plane lower surface 37 engageable with the element to be gripped. That is to say, the lower surface 37 is not provided with knurl ridges and the like as in conventional jaw members. The lower surface 37 may, however, be provided with grooves for receiving peripheral portions of the element to be gripped so that the element to be gripped is centered with respect to the gripping apparatus 10. These grooves, however, also are plane.

The lower gripping member 22 has an upper surface 38 which is opposite to the upper gripping member 20 and has formed therein a generally U-shaped depression 40. A major portion of the U-shaped depression 49 comprises an inclined surface 42 having a first end portion 44 and a second end portion 46. Disposed on the inclined surface 42 and normally resting on the second end portion 46 is a roller member 48 preferably formed from hardened and ground steel. The lower gripping member 22 also is preferably formed from hardened and ground steel. The roller member 48 is rollable over the inclined surface 42 about an axis extending transversely of a passageway 50 defined by the plate means 12, 14 and the upper and lower gripping members 20, 22. The passageway 50 includes an entrance 52 positioned adjacent to the first end portion 44 of the inclined surface 42 and an exit 54 positioned adjacent to the second end portion 46 of the inclined surface 42.

As can best be seen in FIG. 2, an elongated element indicated by the dash-dot outline numbered 56, may be inserted through the passageway 50. Movement of the element 56 to the right of FIG. 2 is unhindered. However, movement of the element 56 to the left of FIG. 2 is not possible. As should be evident, when an attempt is made to move the element 56 to the left of FIG. 2, the roller member 48 will roll up the inclined surface 42, by virtue of its contact with the element 56, thereby converging with the upper gripping member 20 to effect clamping of the element 56 between the upper gripping member 20 and the roller 48. Thereafter, when the element 56 is moved to the right of FIG. 2, the roller member 48 will roll down the inclined surface 42 thereby diverging from the upper gripping member 20 to effect release of the element 56.

It is important to note that the roller member 48 is in direct line contact with the element 56. Thus, that portion of the total gripping force provided by the roller member 48 is concentrated along a line rather than being spread over an area as is the case in prior gripping apparatus. Furthermore, the total gripping force is directly proportional to the amount of pull exerted on the element 56 or on the gripping apparatus. That is to say, as the amount of pull exerted on the element 56, for example, is increased, there will be a corresponding increase in the gripping force. This should be evident since movement of the roller member 48 up the inclined surface 42, i.e., to the left of FIG. 2, moves the roller member 48 closer to the upper gripping member 20 thereby increasing the amount of gripping force provided thereby. Alternatively, the lower gripping member 22 may be provided with a row of the inclined surfaces 42 each having a roller member 48 disposed thereon. In this manner, the total gripping force provided by the plurality of roller members 48 is distributed evenly along a plurality of parallel lines, i.e., along the line of contact between each roller member and the element 56.

Although the gripping apparatus 10 provides for firmly and automatically gripping an element, it also has the desirable feature of quickly and automatically releasing an element when desired. Mere movement of the element 56 to the right of FIG. 2 will cause the roller member 48 to diverge away from the upper gripping member 20 thereby releasing the element 56.

Hence, this embodiment of the present invention provides means for automatically gripping and releasing an element inserted between the upper and lower gripping members 20, 22. In order to take advantage of these features, each of the plate means 12, 14 may be provided with extensions 58 at the bottom thereof, one each extending from each side thereof. A fastener 60 (FIG. 1) extends through each of the extensions 58 and serves to secure a clamping member 62 to the extensions 58. The clamping member 62 includes legs 64, one each at each end thereof which are disposed between the extensions 58 and the clamping member 62. The clamping member 62, the legs 64 thereof and the lower gripping member 22 cooperate to define an opening 66 extending transversely of the gripping apparatus 10. Thus, the gripping apparatus 10 is adapted for mounting on a carrier member, indicated by the dash-dot outline numbered 68 (FIG. 1) which may be inserted through the opening 66. The gripping apparatus 10 may be clamped at any point along the length of the carrier member 68 simply by loosening the fasteners 60, moving the gripping apparatus 10 to the desired position and tightening the fasteners 60.

As an example of the versatility of the gripping apparatus 10, reference is directed to FIG. 3 wherein there is schematically illustrated, the gripping apparatus 19 in conjunction with an extrusion apparatus 70 having a die block 72 through which an elongated plastic element 74 is extruded. The gripping member 10 is shown mounted on the carrier member 68 and is movable thereby between the positions indicated by the extension lines labeled X and Y. The distance between the positions X and Y has been shortened in the drawing.

The operation of the apparatus of FIG. 3 comprises movement of the gripping apparatus 10 from point X to point Y during which the elongated element 74 is gripped and pulled. Immediately upon moving the gripping apparatus 10 to the right of FIG. 3, the elongated element 74 is gripped, as explained above, and pulled. When the gripping apparatus 10 reaches the position Y, a switch means (not shown) is tripped which causes reversal of the drive means (also not shown) driving the carrier member 68 so that the gripping apparatus 10 is moved to the left of FIG. 3 and back to the position X. Immediately upon the reversal of its direction of movement, the

gripping apparatus will release the elongated element 74, as explained above, whereby its backward travel is unhindered. Upon reaching the position X, a second switch means (not shown) is tripped which again reverses the drive means whereby the gripping apparatus is again moved to the right of FIG. 3. Of course, movement of the gripping apparatus 10 to the right of FIG. 3 will be accompanied by an immediate gripping of the elongated element 74. Thus, the elongated element 74-, as it is extruded from the extrusion apparatus 70, is progressively moved away from the die block 72 so that additional lengths of the elongated element 74 may be extruded.

The important fact to note is that the gripping apparatus 10 operates automatically to grip and release the elongated element 74 at appropriate intervals. Thus, it should be evident that the time required to produce a given length of the element 74 is governed primarily by the speed with which the extrusion apparatus 70 may extrude the given length. Only a fraction of the total time required to produce the given length of the element '74 is attributable to the length of time required to return the gripping apparatus 10 to the position X. Furthermore, the only adjustments required on the gripping apparatus 10 are those of replacing the upper gripping member with one which permits convenient gripping of the element 74 (depending on its cross section) and the lowering or raising of the upper gripping member 20 to correspond with the thickness of the element 74. However, once these adjustments have been made, no further adjustments are necessary or required.

A further alternative embodiment of the present invention is illustrated in FIGS. 4, 5 and 6. Corresponding numerals will be employed to identify corresponding parts already described.

In this embodiment, a gripping apparatus 80 is provided with the upper and lower opposed gripping members 20, 22. The lower gripping member 22 is provided with the inclined surface 42 which preferably is inclined at an angle of 10 indicated at A. A roller member, generally designated by the numeral 82, is formed in a plurality of roller segments 84, 86, and 88. Each of the roller segments is provided with a central bore 90 all of the same outer diameter. Each of the roller segments 84, 06, 88 is provided with a central bore 90 of a predetermined diameter through which extends a pin 92 of smaller diameter. The pin 02 serves as a connecting element in that each roller segment is limited to individual movement along the inclined surface 42 through a distance equal to onehalf the diameter of the bore 90. This small individual movement of each of the'roller members 84, S6 and 88 provides a means by which minor variations in the thick nesses of the elements to be gripped may be compensated.

The gripping apparatus 80 thus is adapted to grip a plurality of elements, illustrated herein by the dash-dot lines numbered 94. In order to maintain the elements 94 spaced from each other, at least until they are gripped by the apparatus 80, the upper gripping member 20 preferably is provided with grooves 96 each of which conforms in part with the cross-sectional outline of the element 94. It is important tonote that the peripheral surface of the grooves 96, Le, the surface upon which the elements 94 are engaged, is a plane surface. That is, they are not provided with the knurled ridges as in the case of conventional jaw members.

To illustrate the relative movement of the roller members S4, 86 and 88, reference is directed to FIG. 6. As can be seen, the roller member 86 is shown displaced in a forward direction with respect to the roller members 84, 83. During this forward movement of the roller member 86, the pin member 92 will be moved so as to engage the forward peripheral edge of the bore 90 of the roller members S4, 88 and the rear peripheral edge of the bore 90 of the roller member 86. In this extreme position of forward movement, the pin member 92 connects the roller members 34, 86 and 88 so that thereafter they will move together. Since the roller members b4, 86 and 30 move along the inclined surface 42, the roller member 86 will also undergo vertical movement, that is, it will converge toward the element to be gripped. Hence, it is possible to compensate for minor variations in the thickness of the elements 5 4 (FIG. 5).

A further alternative embodiment of the present gripping apparatus is illustrated in FIGS. 7 and 8 and is generally designated by the numeral 100. Corresponding numerals will be employed to identify corresponding parts already described. The gripping apparatus 100 of this embodiment is particularly adapted for use in drawbenohes, stretcher leveler apparatus and the like. That is, the gripping apparatus 100 norm-ally will be maintained in a horizontal position as shown in FIGS. 7 and 8. In drawbenches, for example, square, rectangular or otherwise shaped elements may be drawn through reduction dies. Normally a plurality of the gripping apparatus 100 will be gauged together to draw a plurality of elements. In stretcher levelers, for example, a plurality of the gripping apparatus 100 will be mounted in side-by-side relation and employed to grip metallic sheets having ripples or corrugations therein which were formed during the manufacture of the sheets.

Referring now to FIGS. 7 and 8, the gripping apparatus 100 comprises a pair of opposed gripping members 102, 104 each supported on arm portions 106, 108 extending from a central Web 110 of a supporting member generally designated by the numeral 112. The grippin-g member 102 is slidably engaged with an inclined surface 114 of the arm portion 106 for movement to- Ward and away from the gripping member 104. A spring member 116, interposed between the central web 110 and the gripping member 102, serves to bias the gripping member 102 toward the gripping member 104. Hence, when an element indicated by the dash-dot line 118 is inserted between the gripping members 102, 104, the gripping member 102 will automatically adjust its position to correspond with the thickness of the element 118. Pin members 120 each project from one side of the gripping member 10 2 through an elongated opening 122 formed in a cover plate 124 and a plate extension 126 contiguous with the arm portions 106, 108. The elongated openings 122 are parallel with the inclined surface 114 of the arm portion 106 and thus serve as bearing surfaces upon which the pin members are slidable and by which the gripping member 102 is maintained with the inclined surface 114 of the arm portion 106. The pin members 120 serve as means for moving the gripping member 102 to the left of FIG. 7 thereby releasing the element 118. In drawbench or stretcher leveler apparatus, means may be provided operable on all of the pin members 120 of all the gripping members 102 for moving them simultaneously thereby simultaneously releasing the elements or element gripped.

The cover plate 124 and .the plate extensions 126 each have formed therein an entrance slot 128 through which the element 118 is introduced between the gripping members 102, 104. V

In this embodiment, the gripping member 100 has provided thereon a row of the inclined surfaces 42 each having a roller member 48 disposed thereon as in the embodiment of FIGS. 1 and 2. Each of the roller members 48 is rollable over its associated inclined surface 42 whereby movement thereof to the right of FIG. 7 will cause clamping of the element 118 between the roller members 43 and the gripping member 102 along a plurality of parallel lines extending transversely of the element 118; and movement thereof to the left of FIG. 7 will cause the release of the gripping force provided by the roller members 48 so that movement of the gripping member 102 by means of the pin member 120 will permit the extraction of the element 118 from the gripping apparatus 100.

The gripping apparatus 106 may, at one time or another, be positioned vertically, horizontally, inclined or in any desired position. Thus, in order to prevent the roller members 48 from falling out of the gripping apparatus 100, there are provided retainer plates 13%, best illustrated in FIG. 8, each of which is secured to one side of the gripping member llM, for example, by means of a plurality of fasteners 132. Each of the retainer plates 130 has a generally U-shaped transverse cross section providing a depression 134 within which reside studs 136, one each projecting from each end of the roller members 48. The upper edge of the retainer plates 134 projects above the studs 136 for a distance sufficient to permit adequate rolling movement of the roller members 48 along the inclined surfaces 42. Furthermore, the upper ends of the retainer plates 130 are disposed below the upper surface of the roller members 48 so that they will not interfere with the insertion of the element 118 between the gripping members 192, 164, as shown in FIGS. 7 and 8.

A further alternative embodiment of the present gripping apparatus is illustrated in FIGS. 9 and and generally designated by the numeral 140. Corresponding numerals will be employed to identify corresponding parts already described.

The gripping apparatus 140 is particularly adapted for use in pull testing apparatus, i.e., apparatus for testing specimens to determine tensile strength, yield strength, and the like. The gripping apparatus 140 comprises a suitable housing 142 having a central web 144- and arm portions 146, 148 depending therefrom. The arm portions 146, 148 have inclined faces 150, 152, respectively, which converge toward a centerline 154 of the housing 142, in a direction away from the central web 144.

The gripping apparatus 148 includes a pair of opposed wedges or griping members 156, 158 each of which has an outboard surface 160, 162 engaged with the inclined faces 152, resectively. The gripping member 155 is provided with a plane face 164 which is disposed parallel to the centerline 154 of the housing 142. Thus, as the gripping member 156 slides over the inclined face 159, the plane face 164 thereof will be maintained parallel to the centerline 154.

Referring to FIGS 9 and 10, the gripping member 1523 has a plane face 166 in which is formed a depression 168 comprising a plurality of the inclined surfaces 42, In this embodiment, however, the inclined surfaces 42 are interconnected as shown in FIG. 10. That is to say, each inclined surafce 42 begins substantially where the previous inclined surface 4?. ends. Each of the inclined surfaces 42 has engaged thereon a roller member 48. As best seen in FIG. 10, the inclined surfaces 42 are so formed whereby each roller member 48 is in contact with the next adjacent roller member 48. This construction provides a maximum number fo the roller members 58 to be used. At the lower end of the depression 168 there is provided an end wall 170 which serves to stop the associated roller member 48:: during its downward movement. The end wall 17 0 is spaced from roller member 48a by a predetermined distance, the arrangement being such that all of the roller members 48, 48:: may move in unison toward the end wall 170, but when the roller member 480 en- ;gages the end wall 17%, the roller members 48 will be prevented from engaging the next-in-line inclined surface 42.

It is preferred in the present embodiment that the inclined surfaces 42 are sloped at an angle of 10 with the vertical, Furthermore, the inclined surface 152 preferably is parallel to the inclined surfaces 42 and, hence, also is sloped at an angle of 10 with the vertical. Still further, the inclined face 150 preferably is sloped at an angle of 10 with the vertical so that the gripping members 156,

158 will be raised and lowered at the same rate.

A pull test apparatus normally employs two of the gripping apparatus 149 which are disposed in vertical alignment and which oppose each other. Hence, the

8 gripping apparatus 1 h) is provided with the retainer plates 138 which retain the roller members 48, 48a engaged with the inclined surfaces 42 as in the case of the embodiment of P165. 7 and 8.

Each of the gripping members 156, 158 is provided with a pair of the pin members 129 which normally have an operator mechanism operable thereon for moving the gripping members 156, 158 reciprocally along the inclined faces 169, 162 for the purpose of clamping or releasing a test specimen. A suitable means is illustrated in dash-dot outline in FIG. 9 and may comprise, for example, a pair of arms 172 pivoted at their upper ends at 174 and having a cam slot 176 at their lower ends through which the pin members extend. A lever arm 178 is pivoted at 180 centrally between the arms 172 and includes a cam 182 engaged with the arms 172. A spring member 184 connects the arms 172 and serves to bias them toward each other.

As shown in FIG. 9 movement of the lever arm 173 in a counterclockwise direction will cause spreading of the arms 172 by the action of the cam 150. When the arms 172 are spread, the pin members 120 will be moved upwardly by the action of the cam slots 176 thereby effecting uniform movement of the gripping members 156, 158 upwardly along the inclined faces 16-3, 162 and away from each other. Thus, a specimen disposed between the gripping mcmbers 156, 153 will be released.

Upon the insertion of a new specimen between the gripping members 156, 158, the lever arm 173 will be rotated in a clockwise direction whereupon the spring member 184 will pull the arms 172 together. When the arms 172 are moved toward one another, the pin members 129 will be moved downwardly by the action of the cam slots 176 thereby effecting uniform movement of the gripping members 156, 158 along the inclined faces 160, 1132 and toward each other. Hence, the new specimen will be lightly clamped between the gripping members 156, 153. During tensioning of the specimen, the roller members 48, 48a will, of course, firmly grip the test specimen.

The gripping apparatus provides an effective means for firmly gripping a test specimen or the like so that the test specimen is always disposed on the centerline 154 of the housing 142.

Although the invention has been illustrated in connection with certain specific embodiments, it will be readily apparent to those skilied in the art that various changes in form and arrangement of parts may be made to suit requirements without departing from the spirit and scope of the invention.

1 claim as myinvention:

1. Gripping apparatus adapted to receive and grip a plurality of elements comprising a pair of opposed gripping members between which the elements to be gripped are inserted; at least one of said gripping members having an inclined surface thereon; at least two roller members disposed on said inclined surface, said roller members normally being aligned on and rollable over said inclined surface about an axis extending transversely of the elements to be gripped; means extending through said roller members for loosely connecting said roller members, said connecting means permitting each of said roller members to roll independently of the other along said inclined surface and through a predetermined distance which is different from the length of travel of said roller members over said inclined surface; said roller members being rollable in a first direction wherein said roller members converge toward the other gripping member to effect clamping therebetween of the element to be gripped and in a second direction, opposite to said first direction, wherein said roller members diverge from the other gripping memher to effect release of the elements gripped.

2. Gripping apparatus adapted to receive and grip a plurality of elements com rising a pair of opposed gripping members between which the elements to be gripped are inserted; one of said gripping members having an inclined surface thereon; at least two roller members disposed in side-by-side relation on said inclined surface, said roller members normally being aligned on and rollable over said inclined surface about an axis extending transversely of the elements to be gripped; pin means extending through aligned openings in said roller members; said openings being larger in diameter than said pin means whereby each of said roller members is movable independently of the other along said inclined surface and through a predetermined distance; said roller members being rollable in a first direction wherein said roller members converge toward the other gripping member to eftect clamping therebetween of the element to be gripped and in a second direction, opposite to said first direction, wherein said roller members diverge from the other gripping member to efiect release of the elements gripped.

3. Gripping apparatus comprising first and second op posed gripping members between which an element to be gripped is inserted; means supporting said first gripping member for movement toward and away from said second gripping member; spring means acting on one of said gripping members for biasing that gripping member toward the other of said gripping members; said second gripping member having at least one inclined surface thereon; a roller member disposed on said inclined surface and rollable thereover about an axis extending transversely of the element to be gripped; said roller member being rollable in a first direction wherein said roller member converges toward said first gripping member to efiect clamping therebetween of the element to be gripped and in a second direction, opposite to said first direction, wherein said roller member diverges away from the other gripping member to effect release of the element gripped.

4. The gripping apparatus of claim 3 wherein said spring means acts on said first gripping member.

5. Gripping apparatus comprising a pair of gripping members between which an element to be gripped is inserted; one of said gripping members having a plane face opposite the other of said gripping members, the other of said gripping members having a row of inclined surfaces thereon of equal inclination; roller members, one each disposed on each of said inclined surfaces and rollable thereover about an axis extending transversely of the element to be gripped; each said roller member being in line contact with adjacent ones of said roller members; all of said roller members being rollable in a first direction wherein said roller members converge toward the other of said gripping members to efiect clamping therebetween of an element to be gripped and in a second direction, opposite to said first direction, wherein all of said roller members diverge from the other of said gripping members to effect release of the element gripped.

6. Gripping apparatus comprising first and second opposed wedging members between which an element to be gripped is inserted; means supporting said wedging members for movement toward and away from each other; means operatively connected to said wedging members for moving said wedging members toward and away from each other; said first wedging member having a plane surface thereon opposite to said second wedging member; said second wedging member having a row of inclined surfaces thereon of equal inclination; roller members, one each disposed on each of said inclined surfaces and rollable thereover about an axis extending transversely of the element to be gripped; all of said roller members being rollable in a first direction wherein said roller members converge toward said plane surface of said first wedging member to effect clamping therebetween of an element to be gripped and in a second direction, opposite to said first direction, wherein said roller members diverge from said plane surface of said first wedging member to effect release of an element gripped.

7. The gripping apparatus of claim 6 wherein each of said roller members is in line contact with adjacent ones of said roller members.

References Cited by the Examiner UNITED STATES PATENTS 225,517 3/1880 Gilman.

557,418 3/1896 Norman.

637,239 11/1899 Davis. 1,208,458 12/ 1916 Benjamins. 1,312,926 8/1919 Sherman 294103 2,368,900 2/ 1945 Templin 73103 X 3,019,522 2/ 1962 Walker.

FOREIGN PATENTS 1,126,098 3/1962 Germany.

652,546 4/ 1951 Great Britain.

35,426 7/ 1922 Norway. 7

OTHER REFERENCES German printed application No. 973,784, June 1960.

WILLIAM FELDMAN, Primary Examiner.

D. GRIFFIN, Assistant Examiner. 

1. GRIPPING APPARATUS ADAPTED TO RECEIVE AND GRIP A PLURALITY OF ELEMENTS COMPRISING A PAIR OF OPPOSED GRIPPING MEMBERS BETWEEN WHICH THE ELEMENTS TO BE GRIPPED ARE INSERTED; AT LEAST ONE OF SAID GRIPPING MEMBERS HAVING AN INCLINED SURFACE THEREON; AT LEAST TWO ROLLER MEMBERS DISPOSED ON SAID INCLINED SURFACE, SAID ROLLER MEMBERS NORMALLY BEING ALIGNED ON AND ROLLABLE OVER SAID INCLINED SURFACE ABOUT AN AXIS EXTENDING TRANSVERSELY OF THE ELEMENTS TO BE GRIPPED; MEANS EXTENDING THROUGH SAID ROLLER MEMBERS FOR LOOSELY CONNECTING SAID ROLLER MEMBERS, SAID CONNECTING MEANS PERMITTING EACH OF SAID ROLLER MEMBERS TO ROLL INDEPENDENTLY OF THE OTHER ALONG SAID INCLINED SURFACE AND THROUGH A PREDETERMINED DISTANCE WHICH IS DIFFERENT FROM THE LENGTH OF TRAVEL OF SAID ROLLER MEMBERS OVER SAID INCLINED SURFACE; SAID ROLLER MEMBERS BEING ROLLABLE IN A FIRST DIRECTION WHEREIN SAID ROLLER MEMBERS CONVERGE TOWARD THE OTHER GRIPPING MEMBER TO EFFECT CLAMPING THEREBETWEEN OF THE ELEMENT TO BE GRIPPED AND IN A SECOND DIRECTION, OPPOSITE TO SAID FIRST DIRECTION, WHEREIN SAID ROLLER MEMBERS DIVERGE FROM THE OTHER GRIPPING MEMBER TO EFFECT RELEASE OF THE ELEMENT GRIPPED. 